As the magnetic recording apparatus becomes small in size and comes to have a large capacity of recording, the magnetic head used in the apparatus is required to be small in size and to have a character to have high density in recording and high efficiency in reproducing. Complying with the requirement, the thin layer process technology used in the LSI device fabrication is applied to fabricate the magnetic head. The magneto-resistive head, which will be simply called "MR head" hereinafter, is a magnetic read head used only for the signal reproduction. The MR head includes a magneto-resistive element, which will be called "MR element" hereinafter, operating under the well-known magneto-resistive effect and has begun to be used greatly. Because, the MR head has a character of reproducing a high output signal voltage in comparison with a usual inductive type head, and the signal reproducing can be performed independently of the velocity of the recording medium.
However, as the size of the magnetic head becomes small because of the advance of the thin layer process technology, the size of the MR element and a magnetic circuit associated with the MR element becomes small. Therefore, the MR head has been required to have high detectivity of the magnetic flux given from the recording medium. The detectivity is generally called "reproducing efficiency" in the MR head.
The magnetic head has two kinds, a separated head and a composite head. In the separated head, a reproducing section including the MR element is separated from a recording section. In the composite head, the reproducing and recording sections are composed such that a magnetic core of the recording section is used as a magnetic shield of the reproducing section commonly.
Furthermore, the magnetic head is classified into two types from a view point of fabrication, a conventional type and a horizontal or a planer type. In either type, the magnetic head is fabricated with the thin layer process technology. That is, a plurality of magnetic heads are fabricated on a flat-substrate as a wafer, and the wafer is precisely cut for producing a plurality of magnetic heads separately. Each of the magnetic heads has a surface faced to the recording medium for guiding the recording medium running, which will be called "guide surface" hereinafter, and a magnetic flux in-out gap placed at the guide surface. The guide surface is for allowing the recording medium to run there above, providing a very small space such as 0.1 micro-meter between the guide surface and the running recording medium. The magnetic flux read-write gap, which will be simply called "gap" hereinafter, is for making magnetic flux input from the running recording medium to the magnetic head in a recording mode and output from the magnetic head to the running recording medium in a reproducing mode. The size of the gap is approximately 0.4 micro-meter.
Thence, in the case of the conventional type, the magnetic head is fabricated so that the guide surface including the gap is provided at a cut surface of the wafer. In other words, the guide surface appears on the cut surface perpendicular to the surface of the substrate. While, in case of the horizontal type, the magnetic head is fabricated so that the guide surface including the gap is provided in parallel to the surface of the substrate.
A problem commonly appearing in all kinds and types of the magnetic head in the prior art is that the reproducing efficiency decreases as the size becomes small because of the thin layer process technology. Another problem appearing in the conventional type magnetic head is that magnetic flux, which will be called "leakage flux" hereinafter, leaking from the MR element to the running recording medium through the gap, damages magnetized substances recorded on the recording medium in the reproducing mode, due to a sense current flowing through the MR element.